The present invention relates to low energy slip rings, and more particularly, to gold based materials for use as slip ring materials.
Materials suitable for use in low energy slip rings must have high wear resistance, low contact resistance, and a homogeneous uncontaminated microstructure. Accordingly, such materials must have high conductivity, high hardness and wear resistance, high tarnish resistance, low contact noise, and little or no tendency toward catalytic formation of friction polymers. In the past, these considerations have led to virtually exclusive dependance upon gold based materials. Currently used gold based materials utilize cold working, solid solution hardening, precipitation hardening, or order hardening, which generally benefits strength, hardness and wear resistance but have detrimental effects on the electrical and chemical properties of gold.
Nickel, cobalt, or cadmimum hardened electroplated gold exhibit high hardness, high wear resistance and have a reasonably high conductivity but such materials often have included contaminants, such as, KCN, porosity, codeposited polymers, and the like. Moreover it is hypothesized that such materials have a non-homogeneous structure. Additionally, the properties of hardened electroplated gold are strongly dependant upon the substrate and plating conditions. Thus, consistently high quality electroplates require not easily achieved stringent controls during processing. Accordingly it is desirable to provide a gold based material which will exhibit high hardness with high wear resistance, high strength and high conductivity with a homogeneous and uncontaminated structure.